Portable self-powered photoelectrochemical immunosensor based on Cu3SnS4 nanoflower for ultra-sensitive and real-time detection of human cytochrome c

The development of sensitive and real-time detection of human cytochrome c (Cyt c) has attracted significant interest since Cyt c plays an important role in programmed cell apoptosis and death, which has been considered an essential biomarker for early cancer diagnosis in human bodies. Herein, a self-powered photoelectrochemical (PEC) immunosensor based on Cu3SnS4 nanoflower is constructed for the ultra-sensitive and portable real-time detection of Cyt c. Systematic studies reveal that Cu3SnS4 has a large specific surface area and appropriate bandgap with excellent visible light absorption, which is beneficial for efficient PEC conversion. The prepared PEC immunosensor shows good reproducibility, high specificity, good storage stability, and excellent detection capability of Cyt c in clinical serum samples. The immunosensor shows dynamic linear detection of Cyt c in the range from 1 fM to 1000 nM along with an ultra-sensitive detection limit of 0.35 fM. Additionally, a portable real-time detection platform of Cyt c is designed, and the platform shows satisfactory linear correlation within the detection range from 1 fM to 1000 nM. We believe that this work provides a useful perspective for manufacturing portable ultra-sensitive and real-time PEC immunosensor for human Cyt c detection in early clinical diagnosis.